Bag opening and spreading mechanism



June 1952 v. G. WILLIAMS BAG OPENING AND SPREADING MECHANISM 3 Sheets-Sheet 1 Filed July 13, 1948 INVENTOR.

5% m M M M m R m% VM J F June 24, 1952 v. G. WILLIAMS 2,601,480

BAG OPENING AND SPREADING MECHANISM 3 Sheets-Sheet 2 Filed July 13, 1948 INVENTOR. V/CTOR. GW/LLl/INS ATT'Y 0 .5 M .Y Q m M a w w T n M A 0 M m W m h Du S e 3 m m M m V m A 2 W 6 0 7 4 00 O 6 M m 2 -I M 3 .3 8 5 4 Mb 5 6 Mm N v .4 0 V 4 A um 96 W W mm HF HQ r w I 5 GW as 2 A o 4 VG m y 0 a m P o o w 0 m B June 24, 1952 Flled July 13 1948 Another such part is the eccentric means for delivering reciprocating power from the driving mechanism of the packaging machine to the instant apparatus, the said eccentric means consisting of a crank member II mounted on rotating shaft S and associated with pitman I2. The reference letter F is generally applied to the packaging machine frame and/or to various portions thereof. I

One of the broad objects of the invention is achieved by restrainably poising a movable panel engaging element above the .bag I. Resilient bag-entering tension is constantly maintained thereon which, when the restraint is removed, moves the said element only so far as will enable it to operate on the bag I without damaging it, irrespective of the speed at which the process is performed.

It should be noted that herein, the term opening is restricted in application to the bag mouth only while the other more comprehensive terms, spreading or expansion, refer to the entire bagll.

The instant apparatus includes a ram I which is reciprocable in a channelled ram guide It carried by the frame F of the packaging machine. From its upper portion projects a wrist pin I1 to which the pitman I2 is suitably connected. Enclosing the ram I5 in its guide I6 is the cover plate I8 which is secured to the said ram guide I6 either directly or, as may be necessitated by the size of the ram I5, through shims I9, and has a median slot 2|] for the wrist pin I1. Beyond the lower end of the ram guide I6, the cover plate I8, still slotted, is inclined away therefrom terminating in a boss 2| housing a through-going, headed, spring controlled bumper 23.

Also suitably secured to the frame F is an open ended magazine 25 for a stack 26 of bags I which is equipped with conventional stack advancing means such as spring 24. A stop 21 is fixed to the frame F at the delivery end of the magazine 25 .tapering to a chisel-pointed offset claw 23 which is so positioned relative to the magazine 25 that it is adapted to engage the top flap 4 of the bag I leading the stack 26 thereof. Moreover, its position is also such that it extendsto but does not intersect the path of the ram I5 for reasons which will duly appear. Air passages 29 therein from an air hose connecting nipple 38 are adapted to conduct and discharge air, whether continuously or intermittently, through the offset claw 28 of the stop 21. When so discharged, the air tends to puff open the mouth of the leading bag I. It should be observed that the pressure of the spring 24 on the stack 23 is communicated therethrough and causes, in effect, theflap 4to begrasped by stop 21. V

The means for completing the preliminary opening of the bag I includes a hair-pin shackle 34 saddled over the wrist pin I1 between pitman I2 and ram guide cover plate I8 and terminating in bushings 35-35 accommodating trunnions 36-36 trammeled in slots 31-31 formed in walls 38-38 projecting from juxtaposed angle brackets 39-39 secured to the said cover plate IS. The said trunnions 36-36 extend from one end of a finger 40 which, passing through and playing in the cover plate slot 20, is adapted to reach to and contact the offset claw 28 of the stop 21, being poised for entry into the leading bag I. By referring particularly to Figs. 1, 2 and 3 of the drawings, it will be seen that when so disposed the intermediate portion of the said finger 40 thus intersects the path of the ram I5.

A tension spring 4| anchored to the boss 2I is connected to the finger 40 in such wise as to urge the free end thereof against the stop 21, which said free end is somewhat offset and chisel pointed and is hereinafter referred to as its claw 44. It is noteworthy that the said tension spring II also applies a downward pull to the finger 40 urging its entry into the bag I but that such movement is restrained or counteracted by the shackle 34 when it is raised by ram I5 through the intermedium of wrist pin I1.

Thus as ram I5 and wrist pin I1 begin their descent, and thereby remove the restraint on the wrist pin saddling shackle 34, the tension spring M is permitted to pull the finger trunnions 36-36 down in the angle bracket slots 31-31 whereby the co-moving finger claw 44 slides down the stop 21 into the bag I in front panel 2 engaging position; the said slots 31-31 limiting the depth of penetration thereinto and hence precluding injury to the bag I irrespective of the speed at which the entry is efiected. Continuing its movement to its next ensuing position with the wrist pin I1 travelling inside shackle 34, the ram I 5 then intervenes between the stop 21 and the finger 4U, diverting the latter with the front panel 2 towards the bumper 23 between which two elements the said front panel 2 is grasped.

The mouth of the bag I being thus fully opened,

the ram I5 assumes its next position in the bag and from the finger 40 and bumper 23 on theother hand and carries it towards the conveyor 8 lying therebelow in one of whose sockets 9 it is then deposited. This being the bottom of its stroke, the ram I5 then rises, passing the finger 40 which is then restored by tension spring 4| to pre-intervention position, and re-engages shackle 34 raising it and finger 40 to the positions initially occupied thereby at the commencement of the downward stroke. This completes one up-and-down cycle of the ram I5.

As has been already said, one of the objects of the invention is to impart a flat rectangular character to the bag bottom 6 as shown particularly in Fig. 5 and identified by reference 6. Prior to this step the bag I is substantially wedgeshaped (Fig. 4) with the folded gussets 5-5 caught at the bottom 6 of the bag I. Thus, to facilitate its entry thereinto, the terminus or head 45 of the ram I5 is tapered as illustrated and is hollowed, moreover, to accommodate the bottom forming mechanism to be described.

The said mechanism includes a recessibly projecting plunger 46 having a shaft 41 and a tongue 48, the upper portions of whose sides incline towards and merge with the shaft 41, the said inclined portions being hereinafter termed the slopes 49-49. The plunger 46 is movable axially of the ram I5, its shaft 41 being fitted with a compression spring 50 and slidably engaged in a bearing 5I suitably disposed in and forming an integral part of the head 45. Fastening means,

the bearing 5| which latter element also forms 511 one abutment 'for the compressionspring 50, the otheri-beinglshoulder 504 on: shaft 41.

Flanking the plunger 46 are 'aipair ofisubstantially triangular spreaders 5252 eachwhereof is expellably suspended byits apex inside the head 45, being adapted to be expelled therefrom throughia slot 53in-the side ci-thesaid head 451 One-side or iaeet 5 l-of-each spreader 52 isadap'ted to abut .a plunger slope 49 through whose -interaction the: said spreader 52 is pressed outwardly o'r expelled 'fronrthe head 45- as I the plunger '45 is pushed back thereintob One or more pull springs 55 interconnect the spreaders 51-52, through suitable media, whereby they are retractable back into the said head 45 as the counterzpressurethereon is abated.-

Itwvill now beapparentthettifihen the ram l5 enter rthelbag. I and .carries it"to the socket!) on the.=conveyor 8 inMthemanner hereinbefore described, the plunger tongue 48 will strike the socket bed I and be thus recessed into the ram head 45 expelling the spreaders 52-52 and forcing them against the bag gussets 5. These latter members being cemented in tucked-in position as aforesaid, the eifect of the spreaders 52- 52 thereon is to form a new transverse crease 5 in each thereof adjacent the new bottom 6 thus causing or at least assisting the gussets 5-5 to assume a desirable perpendicularity.

The thickness of the head 45 being substantially equal to the corresponding dimension of the bag I, it is adapted to crease the panels 2 and 3 accordingly, which effect combines with the new gusset creases 55' to completely reshape or square the bag bottom 6 of Fig. 4 to the form denoted by reference 6 in Fig. 5.

According to the nature of the bag material, the effect of the new gusset creases 5'5 may be found inadequate to completely perpendicularize the gussets 5-5 whereby to maintain the mouth of the bag I as fully open as is necessary, for filling purposes for example. To obviate this contingency it has proven efficacious to form a second transverse crease or dent 60 slightly below the top edge of each gusset 5.

For this purpose there is provided a rib 6| at suitable bag-entering level on each side of the ram l and a ram contacting roller 62 formed of. or at least rimmed with, rubber or other comparable resilient substance, mounted on the frame F.

Thus while the ram I5 is carrying the bag I to the conveyor 8, the rib 6| will pass the roller 62, pressing thereinto through the bag material to form the dent 60.

It will be seen that each roller 62 has the additional advantageous faculty of ironing out its associated gusset 5 against the ram 15 whereby to further stifien it.

It need hardly be pointed out that when the ram I5 is raised to complete the cycle, the compression spring 5| will again eject the plunger tongue 43 thus enabling the pull sprin 55 to retract the spreaders 5252 to pre-expulsion position,

In Figs. 12 and 13 of the drawings appears a modification of the bottom forming mechanism hereinbefore described and illustrated in Figs. 8, 9 and 10; the principal object of the modification being to do away with pull springs 55.

epar't plunger 45 in mama: has a tong u'e Mano; slopes 15-45 adapted to co operate withiac 12 -12 0fT'the-n'ew spreaders'--1E! "-*10. Herein however, the plunger head lfi has another pair satisfactory; and has hi lob been s'leted' IOTHIIHS trativepurpeses; flower/emit is w eu understood that many structuralmhanges -can lde 'niade iri the apparatus herein described which "may make for equal or lesser efiiciency. These, together with certain structural details which are common to the art, having been omitted herefrom for the sake of simplicity and clarity, it is not to be construed that such omission constitutes an abandonment of any of the forms of the invention which falls within the purview of the following claims.

What I claim as my invention is:

1. Opening means for a bag having opposed panels comprising, a fixed stop element adapted to engage the inner face of one of said panels as a bag is fed laterally thereto, means for feeding and guiding bags to said stop, a pivotally supported finger having its free end adjacent said stop element and directed generally inwardly of said bag, the pivotal support for said finger being mounted for limited sliding movement relative to said stop in a direction to project said finger inwardly of said bag between said panels, spring means urging said pivotal support in said direction, and a member movable from a retracted position to a position in said bag between said stop and said finger to thereby swing said finger about its pivot and move said panels apart, said movable member having a portion movable therewith and connected to said pivotal support by a lost-motion means to hold said finger out of said bag against the action of said spring while said movable member is in said retracted position.

2. A device as defined in claim 1 including stop means limiting projecting movement of said pivotal support.

3. Mechanism for opening a bag having opposed fiexible panels joined by longitudinally folded gussets comprising, means including a ram mounted for reciprocatory movement into and out of said bag to separate the said panels and thus open the bag, ribs carried by said ram adjacent the inner surfaces of said gussets and extending transverse to the direction of ram movement, and resiliently distortable means positioned closely adjacent the outer faces of said gussets and the path of movement of said. ribs whereby movement of said ram into said bag causes said ribs to press said gussets against and into said resilient means and impress in said gussets a crease transverse to said longitudinal fold.

4. Mechanism for opening a bag having opposed panels joined by a longitudinally folded gusset comprising, means including a ram mounted for reciprocatory movement to move one end thereof into and out of said bag to separate the said panels and thus open the bag, said ram having a transverse opening adjacent said end, a movable element movable to a position where it is wholly contained within said opening, mean normally holding said element within said opening, and means responsive to movement of the ram to the bottom of said bag for moving said element outwardly of said opening to engage and expand said folded gusset, said ele ment having a gusset engaging portion movable therewith along a transverse path closely adjacent the plane of the end of said ram.

5. A device as defined in claim 4 wherein said ram movement responsive means includes an actuator in said ram and having a part normally projecting from the end of the ram, said actuator being moveable to retract said part into said ram, and inter engaging means between said actuator and moveable element.

VICTOR GEORGE WILLIAMS.

8 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

